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iPod 4G Audio Defect: The Details and Test

This page is a central hub summarizing known information on an audio defect affecting certain fourth-generation (4G) iPods. Our previous news stories on the topic are available here, here, and here.

What is the Audio Defect: “Users of affected iPods will be able to hear a hard disk-like whirring sound in their earphones, coupled with several seconds of light static at the start of a song that has just been loaded. This should not be confused with the quiet hard disk loading sounds that an iPod makes, which sounds are not audible through earphones, or with normal static-like compression artifacts in your audio.”

Who is affected by the Audio Defect: iLounge initially believed that the Audio Defect was limited to a small number of units, perhaps only 40GB iPods, as three of iLounge’s four total 40GB test units have now exhibited the problem. However, user comments subsequently established that both 20GB and 40GB units are affected. The exact number of problem units is not known, or for that matter knowable. iLounge has been gathering user input for three weeks, and emphasized “that [while] the results of our inquiry are comprised of strictly voluntary submissions from readers, and should not be taken as scientific or conclusive, they do suggest that the problem may be more widespread than we had originally hoped.” The most recent requests for positive or negative test results have yielded hundreds of responses from users around the world. Approximately 42% of responding iLounge users reported the audio defect in one or more of the 4G iPods they purchased or received in exchange.

How can you test a 4G iPod for the Audio Defect: “To test your iPod while eliminating the possibility that static from your music or headphones may be responsible, use iTunes to encode several three- to five-minute compact disc tracks using Apple’s Lossless Audio encoder, transfer them to your iPod, then connect the earbuds packaged with your new iPod. Find the directory or create a playlist with only the Lossless tracks, and skip back and forth between them. Hold your iPod at a distance or cover it up so that you can’t hear its normal internal hard disk sounds. If your iPod has a problem, at the start of each loaded song, you should hear a loading pause, then a whirring sound and light static in your ears at a normal volume level. If it does not have a problem, the song should load and play without audio interference.”

Common misconceptions regarding the Audio Defect:

The problem is not caused by Apple Lossless encoding. iLounge’s testing procedure recommends Apple Lossless solely because large file sizes cause more frequent accesses to the iPod’s hard drive, therefore more quickly revealing the problem on an affected iPod.

The problem is not caused by Chinese manufacturing per se. iLounge posted details regarding its test units (shipped from Shanghai, China) in an effort to help Apple and possibly affected users identify a specific plant from which affected units were being produced.

The problem is not limited to orders coming from the Apple Store or to the United States. Issues have been reported in 4G iPods purchased from different stores in different countries.

The problem is not the same in all affected iPods. iLounge has now heard affected iPods where the noise is only audible in one of the two headphones, and others where it is audible in both headphones at once. Some affected iPods appear to make the sounds loudly, while others appear to be more mild.

The problem is not identical to problems in prior-generation iPods. Some users of older third-generation iPods and iPod minis have reported similar sounds that appear only when charging and using accessories connected to the Dock Connector port. The current problem manifests when the iPod is not connected to any additional hardware save headphones, and typically can be heard overlapping the music with static.

The problem does not exist in a unit just because it makes hard disk access noises. Every iPod contains a hard disk that loads data in chunks during playback, and this hard disk is not supposed to be silent - but you shouldn’t generally hear it inside your headphones. Hard disk access noises coming from the iPod’s case (and audible without using headphones) are totally normal. The Audio Defect only exists when you can heard the sound of hard disk accesses accompanied by static coming through the headphones attached to the iPod. Some users have reported that audio played through the Dock Connector port exhibits the same issues.

Added Aug. 23, 2004: The iPod’s part numbers are of no aid in sorting problem units from non-problem ones. Apple’s two current model units (M9282LL/A - 20GB, M9268LL/A - 40GB) are uniformly identified by these part numbers, and contrary to rumors that have been floating around, to the best of iLounge’s knowledge there is no “fixed” M9282LL/C or M9268LL/C version of either product.

What is Apple’s official position on the Audio Defect?(Updated 9-17-04) We have continued to request comment from Apple regarding the Audio Defect, and in response to a September 16 inquiry, an Apple iPod team representative responded on September 17, 2004 that “Apple does not have any comment at this time.” We had previously noted that Apple had not commented on the record to iLounge since late July, at which time the company indicated that it was still looking into the issue. Some users whose units exhibited the problem have reported receiving exchanges from Apple Store locations and certain other Apple-authorized retailers.

What is iLounge’s position on the Audio Defect? Our concern is first and foremost for our readers, and we take pains to promote iPods and related products that provide the most trouble-free and positive experiences for our readers. iLounge informed Apple Computer of its findings immediately after discovery in an effort to minimize the Defect’s impact upon iPod users, and provided its own affected units to Apple for testing. In the absence of further official comment from Apple, iLounge continues to consider this issue a serious one, and thereby reluctantly but strongly cautions its readers to purchase their 4G iPods only from retailers with complete return policies, or to hold off on 4G iPod purchases until Apple confirms that the issues are being addressed.

Is there a fix for the Audio Defect? (updated 11-1-04) As pointed out in early October by reader Jeff L. (and reported in iLounge Backstage), an almost identical problem was identified by Rio, makers of the Carbon audio player, which agreed to alter its manufacturing processes to eliminate the problem in their hardware altogether. We believe that this is the most appropriate course of action, as it requires owners to expend the least effort themselves to get fully working hardware. iLounge users have recently reported that they have returned 4G iPod units to Apple for repair and received fully working units in exchange, indicating that Apple is capable of diagnosing and remedying the problem. As a temporary solution for users who are not as concerned about the cosmetic appearance of their iPods, some users have reduced Audio Defect-related noises by placing a piece of tape or plastic between the iPod’s headphone port and the flat metal edge of the headphones’ plug, preventing any metal-on-metal contact other than the tip of the headphone plug. Thanks to JC and others in the thread for pointing this out.

Are there any updates on the Audio Defect? (updated 11-1-04) None officially through Apple. As iLounge has previously reported, a similar (albeit quieter, in our testing to date) defect appears to exist in the new iPod Photo, as well.